This judge is banning the sharing of someones thoughts as expressed by the written word. The reason being that such information may be used by someone else to cause harm to others. The notoriously liberals 9th ruled against this already because they saw the incrediblly slippery slope that would be caused by the ban. As of yet, no one has died from the manufacture and use of this 3D gun. However, 100 million people have died in the 20th century because of the thought of Marx as expressed in words. The same logic applies to banning Marxist/Communist literature as the gun plan ban.

This is a different matter from the judge in Pennsylvania; this judge is under the jurisdiction of the 9th Circuit Court, which made the original ruling allowing the release of the plans. I wouldn't be surprised if he's censured by the higher court for this injunction - whether it's enforceable or not.